Furniture-caster



(No Model.)

Y F. M. LBGHNER.

FURNITURE GASTBR. No. 388,985. Patented MarpSO, 1886.

MlrLESSES- hvgllml www UNITED STATES FRANCIS M. LECHNER,

PATENT OFFICE.

on ooLuMEUs, oHio.

FURNITURE-CASTER.

SPECEFICATION forming part of Letters Patent No. 338,985, dated March 30, 1886.

Application filed January 3l, 1884. Renewed February 27, 1856. Serial No. 193,538.

To @ZZ whom it may concern:

Be it known that I, FnANcrs M. LEOHNER, aresident of Columbus, in the county of Franklin and State of Ohio, have invented a new and useful Improvement in FurnitureOasters; and I do hereby declare the following to be a full, clear, and exact description thereof.

My invention relates to an improvement in fnrniturecasters; and it consists, principally, in a spherical caster roller, which works against two pairs of friction-wheels j ournaled on a disk or plate, the arcs of two opposite rolls composing one pair being parallel with each other and at right angles to the axes of the other pair, and the disk having a central pivot or axial point, on which it may rotate to adj ust itself so that the line of motion shall be in the diagonal of the quadrilateral formed by the axes of the wheels, and all the frictionwheels may turn with the spherical roller whatever be the direction of its axis of rotation.

I will now describe my invention so that others skilledin the art to which it appertains may manufacture and use it, reference being had to the accompanying drawings, forming part of this specification, in which Figure 1 is as side elevation of my improved caster attached to the leg of a piece of furniture. Fig. 2 is a vertical section on the line x a: of Fig. l. Fig. 3 is a plan view of the movable disk and friction-wheels. Fig. 4 is a detached view of one of the friction-wheels.

Like letters of reference indicate like parts wherever they occur.

Fig. l of the drawings illustrates the body or casing which contains and supports the operating mechanism of the caster. It consists, essentially, of a shank, b, capable of being screwed or otherwise tightly tted into the leg a of a piece of furniture or other article, and the hollow cylindrical casing c. Loosely tted within the casing c is a disk or plate, d, the size of which is such that the diameter of a circumscribed circle is less than the internal diameter of the casing, so that the plate may be free to turn horizontally therein. For this purpose there is a small pointed and preferably conical projection, e, on the back of the plate or disk d, which fits into and bears upon the bottom of a correspondingly-shaped cavity in the center of the base of the casing (No model.)

c. rlhe diameter of the conical cavity is somewhat larger than the diameter of the projection c, and is capable of receiving suitable lubricating material, so that the plate shall turn easily upon the point of the projection as a pivot, and friction against the side of the cavity may be prevented.

Mounted upon the outer face of the plate or disk d are frictiolrwheels ffff, adapted to receive a spherical base-roller, g, upon their upper surfaces, the function of said wheels being to lessen the friction of the revolution of the roller within the casing c. For this purpose the friction-wheels are four in number, and are arranged at equal distances around the circumference of the circle circumscribing the plate between frames or cheeks z', which project vertically from the face of the plate d. The friction-wheels are mounted upon trunnions or axles fr, which fit in grooves L in the cheeks fi, so situate that the opposite friction-wheels of each pair may revolve substantially in the same plane and at right angles to the plane of revolution of the other pair of friction-wheels. The grooves h in the cheeks i must be of such depth that a portion of the periphery of each of the friction-wheels may project above the cheeks t' and afford a bearing-surface for the ball or base roller y, which rests upon them. The ball g is preferably but a little smaller than the internal diameter of the casing c, and the depth of the casing is such that a portion of the ball may project beyond it. The ball may be held within the casing by means of a zone-shaped cap screwed over the mouth of the casing around the ball, the smaller and outer circle of the zone being of less diameter than the diameter of the ball; but it is preferably held by notching or cutting away the mouth of the casing c around the ball, as shown in Fig. 1, and compressing the points Z thus formed, so that they may be nearly in contact with its lower hemisphere.

Thus constructed the operation of my improved caster is as follows: Then the furniture or other article to which it is attached is moved, the friction of the fioor upon the ball g causes it to revolve in the direction of the movement of the furniture. If it happens that IOO this direction is in the plane of a pair of oppoits axis to attain such position.

pair, whose plane of motion is rectangular to the line of motion of the ball, would, if the disk d were fixed, oppose and seriously check the revolution the ball by friction against its surface. The forward wheel of the pair which lies in the plane of motion of the ball must necessarily sustain a greater pressure from the ball than its opposite, and this will cause the ball to raise itself slightly upon the face of the forward wheel. Y In this position the plate or disk d is in a state of unstable equilibrium, and a slightly greater pressure upon one of the side wheels than upon the other,` such as will always occur in practice, will make a resultant force in the direction of the arrow in Fig. 3i. e., diagonal to the quadrilateral formed by extension of the lines of the axes of the friction wheels. As the plate el, to which the Wheels are fixed, is pivoted upon its inner face on the base of the casing c, this resultant force will cause it to turn upon the pivot e, and to adjust itself' so that the line of force shall be in the line of motion of the sphere in whatever direction the furniture be moved. By reference to the drawings it will bereadily understood that in no case need the plate move more than forty-five degrees upon Vhen the plate or disk d has so adjusted itself, both pairs of friction-wheels revolve with the ball, one of each pair of opposite wheels turning toward the center of the plate, and the other wheel of each pair turning in the same direction away from the center.

'Ihe advantages of my improvement are its simplicity, ease of adjustment, and the efliciency with which the friction of the casterroller is diminished. It is especially applicable to use in supporting heavy furniture and articles of machinery.

I am aware that furniture-casters have been made having a spherical base-roller mounted within a easing upon two or more friction- Wheels, and that they have been made with a number of such wheels arranged around the periphery of a plate or disk, so that in whatever direction the caster be moved there may be one or more friction-wheels or one or more pairs of friction-wheels upon which the baseroller may revolve. I do not therefore desire to claim the same broadly; but

What I claim as my invention, and desire to secure by Letters Patent, is

In a furniture-caster, the combination, with a ball or spherical roller, of a bearing-disk having a central pivotal point on which it can rotate, and four anti-friction rollers arranged at right angles to each other, the axes of the two opposite rolls being parallel and at right angles to the axes of the other pair, whereby the disk can rotate to bring the line of movement on the diagonal of the quadrilateral formed by the axes of the wheels, so that all the wheels will rotate, substantially as and for the purposes specified.

In testimony whereof I have hereunto set my hand this 28th day of January, A. D. 1884..

FRANCIS M. LEGHNER.

VVitnesses:

THOMAS WV. BAKEWELL, JAMES R. BAKEWELL. 

